WO2000053464A1

WO2000053464A1 - Vibration dampening pivot housing for windshield wipers

Info

Publication number: WO2000053464A1
Application number: PCT/US2000/003099
Authority: WO
Inventors: Susan Hausfeld Moote; Donald B. Moote; Thomas Hanna
Original assignee: Valeo Electrical Systems, Inc.
Priority date: 1999-03-10
Filing date: 2000-02-04
Publication date: 2000-09-14

Abstract

A windshield wiper pivot housing (14) includes a vibrationally dampening element disposed between a receiver housing and an insert receiving a fastener for attaching the pivot housing to a vehicle (32). The insert is unitarily molded to the receiver and is separated from the receiver during the molding operation and isolated from the housing by the resilient dampening element to vibrationally isolate the insert, the fastener and the attached vehicle component from any vibrations imposed on the receiver housing by a windshield wiper drive (24). Ribs extend inward from a sidewall of the housing and outward from the insert for securely engaging the vibration dampening element with the insert and the housing.

Description

VIBRATION DAMPENING PIVOT HOUSING FOR WINDSHIELD WIPERS

BACKGROUND OF THE INVENTION Field of the Invention:

The present invention relates, in general, to vibration dampeners and, more specifically, to vibration dampeners for windshield wiper drives used in automotive vehicles . Description of the Prior Art:

Drive units for windshield wipers are typically powered by small electric motors. In such systems, a wiper arm including a wiper blade is fixedly attached to the drive shaft as the drive unit which is drivable in reversible pendulum motion. A drive unit of this type can also have an electric motor rotating in the same direction of rotation of the drive unit. In addition, a drive unit for windshield wipers can include a supporting structure on which a motor and drive unit and one more wiper shafts drivable in pendulum motion are mounted.

In general, drive units for windshield wipers of this type are fitted to the vehicle body by means of vibration damping means or elastomeric fastening elements which are fixedly mounted at predetermined attachment points on the drive unit which contact vehicle structure, such as a vehicle body panel . Assembly screws extend through the vibration dampening element into fixed engagement with the vehicle component or panel .

One common type of vibration dampener for windshield wipers has a central sleeve which receives the fastening screw or bolt therethrough for fixing the dampening element and/or its surrounding housing to a vehicle component. Elastomeric material is molded about the sleeve in an attempt to dampen vibrations generated by the wiper drive motor from the attached vehicle component by isolating the central sleeve from the remainder of the windshield wiper drive assembly. PCT printed publication O96/20101 discloses such noise and vibration damping fasteners for a windshield wiper assembly. As is described in greater detail hereafter, the central sleeve or insert is originally unitarily molded with the surrounding housing or receiver portion of the windshield wiper pivot shaft housing in which the windshield wiper pivot shaft is mounted in a separate bore in the prior housing. Elastomeric material is then molded about the inner connected insert and receiver housing to surround the insert and the thin webs unitarily connecting the insert to the surrounding receiver housing.

However, such a vibration dampening assembly is not designed to specifically isolate the insert from the surrounding receiver housing since there is no specific provision for breaking or separating the thin webs connecting the insert to the receiver housing. Since relative to the elastomeric material and the receiver housing, the webs frequently do break during tightening of the fastener to the vehicle body panel. However, any such movement is relatively small, such as approximately 0.5 mm. Furthermore, even if the webs are broken, there is no guarantee that they will be separated or disposed in non-contacting relationship with the insert and/or the receiver housing. As such, the webs are still capable of transmitting vibration and noise from the wiper drive unit through the receiver housing to the insert and the integrally mounted fastener and the attached vehicle component or body panel . Thus, it would be desirable to provide a vibration dampener for windshield wiper drives which ensures complete isolation of the vehicle attachment fastener and fastener receiving insert sleeve from the windshield wiper pivot housing. It would also be desirable to provide a vibration dampening element for a windshield wiper drive which has a reduced number of components as compared to previously devised windshield wiper pivot housing assemblies with vibration dampening features and therefore less assembly labor. It would also be desirable to provide a windshield wiper pivot housing with vibration dampening means in which the vibration dampening element/housing interface are designed to maximize stability of the vibration dampening element relative to the housing and the insert while minimizing vibration transmission to the vehicle.

SUMMARY OF THE INVENTION The present invention is a windshield wiper pivot housing having a unique vibration dampening arrangement which minimizes any transmission of vibrations imposed on the pivot housing by the windshield wiper drive unit from the fastener attaching the pivot housing to a vehicle.

According to the present invention, the windshield wiper pivot housing is formed of: a housing having a through bore extending between first and second ends, a fastener receiving insert having first and second opposed ends, a first end of the insert spaced from a first end of the housing, and a resilient body disposed within the housing and completely isolating the insert from contact with the housing.

At least one and preferably a plurality of radially outward extending ribs are formed on the insert. At least one and preferably a plurality of inward extending ribs are also formed on the sidewall of the receiver housing for stabilizing the interface between the housing and the vibration dampening element molded therein and the interface between the insert and the vibration dampening element.

The insert is preferably unitarily formed with the housing and is initially attached to the housing by thin webs extending between the housing and the insert. A first end of the insert projects outward from the first end of the housing and is displaced by engagement with a mold to a second position wherein the first end of the housing and the first end of the insert are substantially in-line and the second end of the insert projects exteriorly of the second end of housing. Vibration dampening, resilient material is then injected into the mold to form a vibration dampening element between the insert and the housing. The vibration dampening element completely isolates the insert from the housing and surrounds all of the exterior surfaces of the insert disposed within and exteriorly of the housing. A unique method of manufacturing a windshield wiper pivot housing is also disclosed. The method includes the steps of: forming a housing having a through bore extending between first and second opposed ends; forming a fastener receiving insert having first and second opposed ends unitarily within the housing; spacing both of the first and second ends of the insert from adjacent surfaces of the housing to isolate the insert from the housing; and unitarily molding a resilient material between the insert and the housing to vibrationally isolate the insert from the housing to dampen any movement of the housing relative to the insert . Preferably, the method includes the steps of forming at least one and, preferably, a plurality of spaced, radially outward extending ribs on the insert and at least one and, preferably, a plurality of radially inward extending ribs on a sidewall of the housing for stabilizing the interface between the vibration damping element and both of the housing and insert .

The method also includes the step of unitarily molding the insert and housing as a one piece unitary assembly by means of thin webs extending between the housing and the insert. A first end of the insert is spaced outward from the first end of housing prior to placing the unitarily formed insert and receiver housing into a second mold. The second mold displaces the insert relative to the stationarily held housing and breaks the webs connecting the insert and housing. This displacement allows the first end of the insert to move into substantial, flush alignment with the first end of the housing and projects the second end of the insert outward beyond the second end of the housing.

The unique windshield wiper pivot housing of the present invention ensures that the fastener receiver insert used to attach the pivot housing to a vehicle is vibrationally isolated from the surrounding receiver in the pivot housing so as to minimize any vibrations in the pivot housing caused by the windshield wiper drive motor from being transmitted to the insert and fastener and then to the vehicle. The pivot housing is formed of a minimal number of components for low assembly labor. Further, unique ribs employed on the insert and the sidewall of the housing stabilize the housing/vibration dampening element interface and the insert/vibration dampening element interface to ensure the complete dampening of vibrations by the vibration dampening element .

BRIEF DESCRIPTION OF THE DRAWING The various features, advantages and other uses of the present invention will become more apparent by referring to the following detailed description and drawing in which:

FIG. 1 is a perspective view of a conventional, prior art windshield wiper drive unit including vehicle body parts to which the drive unit is mounted;

FIG. 2 is an enlarged, perspective view of a prior art windshield wiper pivot housing,-

FIG. 3 is a plan elevational view of the left end vibration dampening element receiver and mounting bolt insert;

FIG. 4 is an enlarged cross-sectional view generally taken along line 4-4 in FIG. 2; FIG. 5 is a perspective view of a windshield wiper pivot housing according to the present invention;

FIG. 6 is a plan elevational view of unitarily molded receiver housing and fastener receiving insert after a first molding operation;

FIG. 7 is a cross-sectional view generally taken along line 7-7 in FIG. 6 ;

FIG. 8 is a lateral cross-sectional view, similar to FIG. 7, but showing the position of the insert after the assembly of FIG. 7 has been placed into a second mold and the dampening material injected therein; and

FIG. 9 is an enlarged, perspective view of the fastener receiving insert shown in FIGS. 5-8. DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is depicted a prior art windshield wiper drive assembly having typical vibration dampening elements mounted at vehicle attachment points, such as windshield wiper pivot housing.

Drive components required for driving the wiper arms, not shown, are mounted on a supporting frame 10 having a connecting rod 12, on which transversely extending bushing-type bearing elements or pivot housings 14, only one of which is shown, are non-rotatably mounted. The bearing element or pivot housing 14 includes a tongue-shaped fastening projection 16 on an outside periphery. A wiper shaft 18 is received in the bearing element or pivot housing 14 in a rotatable, but axially fixed manner. A wiper arm, not shown, is non- rotatably secured to the rotatable wiper shaft 18. The wiper shafts 18 on either end of the connecting rod 12 are driven by a multi part coupling linkage 20 which connects both wiper shafts 18 for synchronized rotation, and by a crank 22 which, in turn, is non-rotatably mounted on the drive shaft, not shown, of a drive motor 24. The drive motor 24 and its associated output gear unit are attached to a bracket 26 mounted on the connecting rod 22. For the vibration dampening attachment of the driving unit to a vehicle body, the supporting frame 10 has elastomeric vibration dampening elements 28 of a hollow or annular cylindrical design which are mounted on the fastening projections 16 of the bearing element or pivot housing 14 and on the bracket 26. The vibration dampening elements 28 are held captive on the fastening projection 16. A fastening screw 30 extends through each bearing element or pivot housing 14 and the vibration dampening element 28 mounted thereon so as to be rotatable yet undetachable from the pivot housing 14. The drive unit is then attached to a predetermined location in the engine compartment of an automotive vehicle to body panels or components denoted by reference number 32. Only two body panels 32 are represented in FIG. 1. The vehicle body panels 32 have an internally threaded attachment bore 34 formed therein which receives the assembly screw 30. Referring now to FIGS. 2-4, there is depicted a windshield wiper pivot housing 40 of the type shown in published PCT application WO96/20101. The pivot housing 40 includes a through bore 42 which is sized for rotatably yet non-detachably receiving a windshield wiper arm pivot shaft, not shown. An arm 44 projects from end of the pivot housing 40 and is attachable to the connecting rod 12 of the supporting frame 10 shown in FIG. 1 by means of a press fit, mechanical fasteners, etc. A vibration dampening element receiver 46 extends from an opposite end of the pivot housing 40. The receiver 46 is formed with a sidewall 47 extending between an open, upper or top end 50 and an opposed bottom or lower end 52. A flange 54 projects radially inward from the bottom end 52 of the sidewall 47 to a central, large aperture 56. The flange aperture 56 shown in FIG. 3 is depicted as having an oval shape as the pivot housing 40 at one end of the windshield wiper drive assembly will typically have a circular opening; while the opposed pivot housing 40 will have an oval opening to accommodate manufacturing part tolerances . A plurality of smaller apertures 58, the purpose of which is to come more apparent hereafter and described hereafter, are spaced about the flange 54. The flange 54, the sidewall 47, the open top end 50 and the central, large aperture 56 cooperate to form an internal cavity 60 in the receiver 46. An insert 62 generally in the form of a cylindrical sleeve and having a through bore 64 is unitarily formed by molding with the sidewall 47 of the receiver 46. During such unitary molding, a plurality of circumferentially spaced, thin webs 66 are formed between the sidewall 47 of the receiver 46 and the insert 62 to centrally locate the insert 62 within the central large aperture 56 in the bottom flange 54 of the receiver 46.

An elastomeric or resilient material is then injected between the insert 62, the sidewall 47 and the flange 54 of the receiver 46 to form a vibration dampening element or mass 68 as shown in FIGS. 2 and 4. During this molding process, the insert 62 is held stationary relative to the surrounding stationarily fixed receiver 46 such that it is common for the thin webs 66 to remain connected between the insert 62 and the sidewall 47 of the receiver 46. Even if the thin webs 66 break during the injection of the elastomeric material between the insert 62 and the sidewall 47, or later during the attachment of the pivot housing 40 to a vehicle body panel, the webs 66 are capable of only a minute amount of movement, such as on the order of 0.5 mm. This minimal amount of potential movement does not guarantee that the webs 66 will be separated from the insert 62 or the sidewall 47 of the receiver 46. At the least, there is no guarantee that the elastomeric material will fill any space between a broken or separated web 66 and the adjacent insert 62 or sidewall 47 of the receiver 46.

Referring now to FIGS. 5-9, there is depicted a windshield wiper pivot housing 80 constructed in accordance with the teachings of the present invention which includes a uniquely configured and mounted vibration dampening element 82. The pivot housing 80 includes a unitary body having a cylindrical sleeve 84 with an internal through bore 86 sized to rotatably receive a windshield wiper arm pivot shaft, not shown.

The shaft is rotatable, but non-detachably mounted within the sleeve 84 in a conventional manner, as shown in Fig. 1. A mounting arm 88 projects from the sleeve 84 and is attachable to the connecting rod 12 of the support frame 10 shown in FIG. 1, by example only.

A receiver or receiver housing 90 also projects from the sleeve 84. Strengthening flanges 92 may be provided between the sleeve 84 and the receiver housing 90 for rigidity. As shown in FIGS. 5-8, the receiver 90 is formed with circular sidewall 94. As in prior art pivot housings, the conventional windshield wiper drive will include two windshield wiper pivot housings, one of which will have an oval shape with a large oval aperture as shown in Figs. 2-4 and the other an annular shaped receiver and large circular aperture, as shown in Figs. 5-8, to accommodate manufacturing tolerances in the windshield wiper assembly and vehicle attachment components. The sidewall 94 extends from an open top end 96 to an opposed bottom end 98. A through bore 100 is formed within the sidewall 94. The bore 100 forms an interior cavity within the sidewall 94 of the receiver 90. A bottom flange 102 projects radially inward from the bottom end 98 of the sidewall 94 and has a large central aperture 104 of either circular or oval shape consistent with the shape of the sidewall 94 of the receiver 90. A plurality of small apertures 106 are formed in the flange 102, the purpose of which will be described hereafter.

An insert 110 is mounted interiorly within the through bore 100 of the receiver 90, generally concentric with the central aperture 104 in the bottom flange 102. The insert 110, as shown in detail in FIG. 9, is in the form of an elongated, tubular body having an oval or circular cross section consistent with the corresponding shape of the central aperture 104 in the flange 102. The insert 110 has a first end 112 and an opposed second end 114 formed in an enlarged diameter lip. A through bore 116 extends between the first and second ends 112 and 114 of the insert 110 for receiving a fastening element, such as a screw or bolt 30 shown in FIG. 1, for fixedly attaching the pivot housing 80 to a vehicle body panel or component 32, as shown in FIG. 1.

According to a preferred method of manufacturing the pivot housing 80 of the present invention shown in FIG. 7, the insert 110 is unitarily molded as an integral, one piece part of the receiver 90. A first mold denoted generally by reference number by 118 in FIG. 7 has an internal cavity shaped to form the receiver 90 and the insert 110 as described above. In this first stage, the first or upper end 112 of the insert 110 projects above the first end 96 of the receiver 90 as shown in FIG. 7. The bottom end 114 of the insert 110 is unitarily connected to the inner edges of the bottom flange 102 of the receiver 90 by means of a plurality, such as two or more, spaced webs 120, with three circumferentially spaced webs 120 being shown in FIG. 6 by way of example only. It should be noted that the bottom end 114 of the insert 110 is flush or in line with the bottom end 98 and bottom flange 102 of the receiver 90. The assembly shown in FIG. 7 is then placed in a second mold denoted by reference number 122 in FIG. 8 which has a suitably formed mold cavity to receive the assembly of FIG. 7 as well as to provide a suitable shape for the vibration element to be formed therein. As the mold 122 is closed, one surface of the mold 122 engages the first end 112 of the insert 110 projecting above the first end 96 of the receiver 90 and forcibly moves the insert 110 relative to the stationarily held receiver 90 to a moved position shown in FIG. 8. This movement which is substantial and on the order of substantially 5 mm, by example only, breaks the webs 120 and spaces the bottom end 114 of the insert 110 a substantial distance from the inner edges of the bottom flange 102 of the receiver 90. A suitable injection moldable elastomeric material, such as an elastomeric material sold under the trade name SANTOPRENE, for example, is injected into the mold 122 and allowed to cure to a solid state. The elastomeric material is injected into the mold 122 between the insert 110 and the sidewall 94 of the receiver 90. It should be noted that the mold cavity of the mold 122 is shaped to allow a bottom end portion 124 of the elastomeric material to be formed below the bottom flange 102 of the receiver 90. The main surface of the bottom end portion 124 is generally aligned with bottom end 114 of the moved insert 110 as shown in FIG. 8. It should be noted that the top surface 126 of the elastomeric material or vibration dampening element 82 is substantially flush with the top or first end 112 of the insert 110 and the first end 96 of the receiver 90.

It should also be noted that the elastomeric material flows through the small apertures 106 in the bottom flange 102 of the receiver 90 to assist in attaching the vibration dampening element 82 to the receiver 90. Additional strength and stability of the interface between the insert 110 and the vibration dampening element 82 and of the interface between the vibration dampening element 82 and the receiver 90 is obtained by forming at least one and, preferably, a plurality of circumferentially spaced, radially outward extending ribs 128 on the insert 110. As shown in FIG. 9, the ribs 128 project from a sidewall 130 of the insert 110 to the outer peripheral edge aligned with the enlarged diameter second end or lip 114 of the insert 110.

At least one and preferably a plurality of radially inward, circumferentially spaced ribs 132 are also formed on the inner surface of the sidewall 94 of the receiver 90. The elastomeric material forming the vibration dampening element 82 fills the spaces between adjacent ribs 128 on the insert 110 and between adjacent ribs 132 on the receiver 90 to stabilize and hold the vibration dampening element 82 in a fixed position with respect to the adjoining sidewall 94 of the receiver 90 and the sidewall 130 of the insert 110 to prevent any rotational movement therebetween. This stability enables the vibration dampening element 82 to be placed in compression and tension under any vibration imposed on the pivot housing 80 without separating from the receiver 90 or insert 110.

In summary, there has been disclosed a unique windshield wiper pivot housing which includes an improved vibration dampening element and mounting structure therefore which improves the stability of the vibration dampening element/fastener receiving insert/receiver housing interfaces. The receiver and insert are designed to ensure separation and movement of the unitarily formed insert relative to the receiver housing by a substantial distance to enable the elastomeric material injected into a mold containing the receiver housing and insert to fill the separated space between adjoining portions of the insert and the receiver to completely isolate the insert from the receiver housing thereby minimizing any transmission of vibrations from by the windshield wiper drive and the windshield wiper pivot housing from the insert, the fastener extending through the insert, and the attached vehicle mounting component .

Claims

What is claimed is : 1. A windshield wiper pivot housing attachable to a vehicle for receiving a windshield wiper pivot shaft, comprising: a housing having a through bore extending between first and second ends; a fastener receiving insert having first and second opposed ends, the second end of the insert spaced from the second end of the housing; and a resilient body disposed within the housing and completely isolating the insert from contact with the housing.

2. The windshield wiper pivot housing of claim 1 wherein: the insert is unitarily formed with the housing by separable webs extending between the housing and the insert .

3. The windshield wiper pivot housing of claim 1 further comprising: the housing having a sidewall; and at least one rib formed interiorly on the sidewall of the housing and extending toward the insert.

4. The windshield wiper pivot housing of claim 3 further comprising: at least one rib formed on the insert and extending outward toward the housing.

5. The windshield wiper pivot housing of claim 4 further comprising: a plurality of spaced ribs formed about the insert and extending outward toward the housing.

6. The windshield wiper pivot housing of claim 4 further comprising: a plurality of spaced ribs formed interiorly on the sidewall and extending radially inward toward the insert .

7. The windshield wiper pivot housing of claim 1 further comprising: at least one rib formed on the insert and extending outward from the housing.

8. A method of manufacturing a windshield wiper pivot housing attachable to a vehicle for receiving a windshield wiper pivot shaft, the method comprising the steps of: forming a housing having a through bore extending between first and second opposed ends; forming a fastener receiving insert having first and second opposed ends unitarily within the housing; spacing both of the first and second ends of the insert from adjacent surfaces of the housing to isolate the insert from the housing; and unitarily molding a resilient material between the insert and the housing to vibrationally isolate the insert from the housing to dampen any movement of the housing relative to the insert.

9. The method of claim 8 further comprising the step of : displacing the first end of the insert outward from the first end of the housing when the insert is unitarily molded to the housing by thin webs extending unitarily between the housing and the insert.

10. The method of claim 8 further comprising the step of : forming at least one radially inward extending rib on the sidewall of the housing.

11. The method of claim 10 further comprising the step of : forming at least one radially outward extending rib on the insert.

12. The method of claim 11 further comprising: forming a plurality of spaced ribs on a sidewall of the housing, the ribs extending radially inward form the sidewall of the housing toward the insert .

13. The method of claim 11 further comprising a step of: forming a plurality of spaced, radially outward extending ribs on the insert .

14. The method of claim 8 further comprising the step of: forming at least one radially inward extending rib on the sidewall of the housing.

15. The method of claim 8 wherein: the steps of forming the housing and forming the insert are performed in a first mold.

16. The method of claim 15 wherein: the step of displacing the insert relative to the housing is formed in a second mold.

17. The method of claim 8 wherein the step of displacing the insert relative to the housing displaces the insert to bring the first end of the insert substantially in-line with the first end of the housing and the second end of the insert projecting exteriorly of the second end of the housing.

18. A method of manufacturing a windshield wiper pivot housing attachable to a vehicle for receiving a windshield wiper pivot shaft, the method comprising the steps of: unitarily molding a housing having a through bore extending between first and second ends and an insert disposed interiorly within the through bore of the housing and having first and second opposed ends wherein the housing and the insert are unitarily connected by separable webs,- disconnectingly spacing the first end of the insert from the first end of the housing,- disconnectingly spacing the second end of the insert from the second end of the housing; and molding a resilient material between the spaced first ends of the housing and the insert and between the spaced second ends of the housing and the insert to vibrationally isolate the entire insert from contact with the housing.